261 research outputs found
Integrated Scheduling of Vessels, Cranes and Trains to Minimize Delays in a Seaport Container Terminal
The multiple processes taking place on a daily basis at an intermodal container terminal are often considered individually, given the complexity of their joint consideration. Nevertheless, the integrated planning and scheduling of operations in an intermodal terminal, including the arrivals and departures of trains and vessels, is a very relevant topic for terminal managers, which can benefit from the application of Operations Research (OR) techniques to obtain near-optimal solutions without excessive computational cost. Applying the functional integration technique, we present here a mathematical model for this terminal planning process, and solve it using heuristic procedures, given its complexity and size. Details on the benchmark comparison of a genetic algorithm, a simulated annealing routine and a tabu search are provided for different problem instances
Simultaneous Planning of Liner Ship Speed Optimization, Fleet Deployment, Scheduling and Cargo Allocation with Container Transshipment
Due to a substantial growth in the world waterborne trade volumes and drastic
changes in the global climate accounted for CO2 emissions, the shipping
companies need to escalate their operational and energy efficiency. Therefore,
a multi-objective mixed-integer non-linear programming (MINLP) model is
proposed in this study to simultaneously determine the optimal service
schedule, number of vessels in a fleet serving each route, vessel speed between
two ports of call, and flow of cargo considering transshipment operations for
each pair of origin-destination. This MINLP model presents a trade-off between
economic and environmental aspects considering total shipping time and overall
shipping cost as the two conflicting objectives. The shipping cost comprises of
CO2 emission, fuel consumption and several operational costs where fuel
consumption is determined using speed and load. Two efficient evolutionary
algorithms: Nondominated Sorting Genetic Algorithm II (NSGA-II) and Online
Clustering-based Evolutionary Algorithm (OCEA) are applied to attain the
near-optimal solution of the proposed problem. Furthermore, six problem
instances of different sizes are solved using these algorithms to validate the
proposed model.Comment: 28 pages, 10 figure
Modeling dry-port-based freight distribution planning
In this paper we review the dry port concept and its outfalls in terms of optimal design and management of freight distribution. Some optimization challenges arising from the presence of dry ports in intermodal freight transport systems are presented and discussed. Then we consider the tactical planning problem of defining the optimal routes and schedules for the fleet of vehicles providing transportation services between the terminals of a dry-port-based intermodal system. An original service network design model based on a mixed integer programming mathematical formulation is proposed to solve the considered problem. An experimental framework built upon realistic instances inspired by regional cases is described and the computational results of the model are presented and discussed
Efficient yard storage in transshipment container hub ports
Ph.DDOCTOR OF PHILOSOPH
Schedule Reliability in Liner Shipping: A Study on Global Shipping Lines
Due to the complex structure of the transportation systems, disruptions in transport operations may occur from time to time. In liner shipping, it is seen that shipping lines frequently deviate from the transit times announced in their vessel schedules, and this leads to schedule unreliability. This leads to schedule unreliability and affects all stakeholders. Based on actual transportation data, this study aims to evaluate the transit time reliability performance of shipping lines and the factors that may affect transit time reliability to investigate schedule reliability in liner shipping. To evaluate the transit time reliability of shipping lines’, transit time deviations were calculated based on observations containing 5080 transport data of shipping lines and current performances are discussed. Hypotheses were tested with independent sample t-test and Welch’s ANOVA to examine the factors affecting transit time reliability. Tamhane’s T2 post-hoc test was used to determine the difference between groups. Results show that transit time reliability of shipping lines is low. It has been observed that the type of service, season, vessel age, and TEU capacity of the vessel factors affect the transit time reliabillity. With this study, shipping lines can evaluate their reliability performances according to the competition. At the same time, lines can use these results to understand, evaluate and manage factors that affect their transit time reliability. In this direction, suggestions have been made to the shipping lines to contribute to improving transit time reliability and service quality. This article is regarded to close the gap in evaluating transit time reliability in liner transportation because it relies on actual transportation data
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